1. Field of the Invention
The present invention is directed to a fastener driving tool having a magazine that rotates around an axis and locks axially into a selected position.
2. Description of Related Art
A fastener driving tool typically has three regions: a back end enclosing a firing mechanism, a front end comprising a muzzle and a magazine, and an intermediate region comprising a tool body. A typical tool includes the tool body and a barrel housed coaxially within the tool body. The barrel contains and guides a piston, driven by the firing mechanism activated by a trigger. A buffer assembly in the barrel stops the flight of the piston. The muzzle, housed within a muzzle housing, extends forward from the tool body and is displaceable from an extended position into a ready-to-fire position when pressed against the receiving substrate.
Fastener driving tools desirably include a contact pressure safety feature assuring that the firing mechanism fires only when the muzzle is pressed against the receiving substrate. When pressed against the receiving substrate, the muzzle displaces into ready-to-fire position and enables the firing mechanism to fire when the trigger is pulled.
In some fastener driving tools, a magazine is coupled to the muzzle in order to minimize fastener loading time. Multiple fasteners, often connected in a assembly called a fastener strip, loaded into the magazine allow the user to fire multiple fasteners before needing to reload the tool. The magazine contains a follower that biases the fasteners toward the muzzle for driving by the piston into receiving substrate.
In many applications it is desirable to allow the muzzle and the magazine to rotate around a tool body axis so that an operator may move the magazine out of the way when driving fasteners into corners or other hard-to-reach places. Mechanisms that allow the magazine to rotate about the tool body axis are generally referred to as magazine clutches.
A magazine clutch must have a means to lock the magazine in place once a desired magazine position has been reached. If a locking mechanism is not employed, the magazine will flop around during operation and will be unwieldy. A prior magazine clutch locking assembly, as embodied in Hilti Model # DX351, locked the magazine in place using spring-biased bearings and receiving sockets to provide inwardly directed radial locking forces between the muzzle and the stator. This embodiment of the radial magazine locking mechanism made the tool bulky and cumbersome to handle.
What is needed is a non-bulky and easy-to-use magazine clutch assembly of a fastener driving tool.
It is therefore an object of the present invention to provide a non-bulky and non-cumbersome locking mechanism that will releasably lock the muzzle and attached magazine in any selected one of predetermined positions.
In accordance with the present invention, a fastener driving tool comprises a tool body having an axis, a piston guided along the axis within the tool body, a muzzle extending forwardly from the tool body, a magazine coupled to the muzzle, and an axial locking mechanism associated with the muzzle. The muzzle and coupled magazine are rotatable around the tool body into at least one releasably locked position.
In another aspect of the invention, a barrel that guides a piston is housed coaxially within the tool housing. An annular stator is coaxial with the barrel, and the muzzle is rotatable with respect to the stator.
The axial locking mechanism comprises male members and female members, with the male members biased axially into the female members. The male members can be disengaged from the female members by application of a predetermined torque with respect to the muzzle. The bias of the male members may be provided by springs. In one embodiment, an axial locking mechanism comprises bearings and sockets, wherein the bearings are biased axially into the sockets.